The World Health Organizatiοn (WHO) classification of eye tumours is a widely used pathologic classification system of neoplasms of the orbit. The revision, part of the 4^th edition of the WHO series, was published in 2018 and is reflected in the article below ¹.

Classification

Tumours of the conjunctiva and caruncle

• epithelial tumours

  • conjunctival squamous cell carcinoma

  • conjunctival spindle cell carcinoma

  • adenosquamous carcinoma

  • keratoacanthoma

  • hereditary benign intraepithelial dyskeratosis of the conjunctiva

  • sebaceous carcinoma

  • oncocytoma

  • conjunctival squamous papilloma

    • tumour-like lesion

    • cysts

    • reactive epithelial hyperplasia

    • pseudoglandular and pseudoepitheliomatous hyperplasia

• melanocytic tumours

  • conjunctival melanoma

  • conjunctival melanocytic intraepithelial neoplasia

  • conjunctival junctional, compound, and subepithelial naevi

  • inflamed juvenile conjunctival naevus

  • blue naevus of the conjunctiva

  • Spitz naevus of the conjunctiva

  • benign epithelial melanosis of the conjunctiva

• hematolymphoid tumours

  • lymphomas

  • papillary/follicular conjunctivitis

  • reactive lymphoid hyperplasia

• soft tissue tumours

  • leiomyosarcoma

  • rhabdomyosarcoma

  • Kaposi sarcoma

  • angiosarcoma

  • fibrous histiocytoma

  • conjunctival stromal tumour

  • myxoma

  • haemangioma

  • lymphangioma

  • neurofibroma

  • schwannoma

  • juvenile xanthogranuloma

• hamartomas and choristomas

  • epibulbar choristoma

  • epibulbar osseous choristoma

  • phakomatous choristoma

• secondary tumours

Tumours of the iris, ciliary body, and choroid

• tumours of the iris

  • iris melanoma

  • melanocytic naevus

  • ocular melanocytosis

  • Lisch nodule

  • pigmented epithelial cyst

  • implantation cyst

  • ectopic lacrimal gland

  • histiocytic tumours

• tumours of the ciliary body

  • uveal melanocytoma

  • adenocarcinoma

  • ciliary body adenoma

  • adenomatous hyperplasia

  • reactive epithelial hyperplasia

  • medulloepithelioma of the ciliary body

  • leiomyoma

  • schwannoma

  • glioneuroma

• tumours of the choroid

  • choroidal and ciliary body melanomas

  • choroidal and ciliary body naevi

  • bilateral diffuse uveal melanocytic hyperplasia

  • neurofibroma and ganglioneuroma

  • schwannoma

  • haemangioma

  • osteoma

  • primary choroidal lymphoma

  • secondary lymphomatous infiltration

  • leukaemic infiltration

• secondary tumours

Tumours of the retina and retinal pigment epithelium

• tumours of the neurosensory retina

  • retinoblastoma

  • retinocytoma

  • astrocytic hamartoma and astrocytoma

  • nodular and massive retinal gliosis

  • haemangioblastoma

  • cavernous haemangioma

  • vitreoretinal lymphoma

  • leukaemic infiltration

  • secondary tumours

• tumours of the retinal pigment epithelium

  • adenocarcinoma

  • adenoma

  • reactive hyperplasia

  • simple and combined hamartomas

  • congenital hypertrophy

Tumours of the optic disc and optic nerve

• primary tumours

  • astrocytoma and glioblastoma

  • meningioma of the optic nerve

  • medulloepithelioma

  • solitary fibrous tumour/haemangiopericytoma

  • melanocytoma

• secondary tumours

Tumours of the lacrimal gland

• epithelial tumours

  • adenoid cystic carcinoma

  • mucoepidermoid carcinoma

  • carcinosarcoma

  • carcinoma ex pleomorphic adenoma

  • pleomorphic adenoma

  • myoepithelial tumours

  • oncocytic tumours

  • rare neoplasms

    • epithelial-myoepithelial carcinoma

    • low-grade intraductal carcinoma

    • secretory carcinoma

    • hybrid neoplasms

    • acinic cell carcinoma

    • Warthin tumour

• hematolymphoid tumours

  • lymphomas

  • reactive lymphoid hyperplasia

• secondary tumours

Tumours of the lacrimal drainage system

• epithelial tumours

  • squamous cell carcinoma

    • non-keratinising squamous cell carcinoma

  • adenocarcinoma

  • mucoepidermoid carcinoma

  • adenoid cystic carcinoma

  • lymphoepithelial carcinoma

  • exophytic papilloma

  • inverted papilloma

• other tumours

  • melanoma

  • lymphomas

  • secondary tumours